Starlet Amanda Bynes was an early adopter to Instagram (last year but you have to move fast in social media to be an early adopter) and has had a number of issues this year but she did find time to post a selfie early in 2013.

Sorry: That should be amended to read the female celebrity bottom; not surprisingly, there aren't a lot of "Hey! Look at my ass!" pictures of famous men on Instagram.

(Well, there might be, but not for the purposes of this discussion. We're talking mainstream fan photos, which are mostly limited to "gotcha" shots of Bieber's backside or various One Direction bottoms. All fairly tame. Okay?

You can see where we're not going with this. )

Back to female celebs and their bare booty shots: should we all be a little alarmed? Beyonce — she's ubiquitous now, really, like Moby Dick — has some very artsy bum shots in her Partition video. The lyrics to Partition ("Look at me! Look at me! Look at me! Look at me! Look at me! Look at me! Look at me! Look at me! Look at me! Look at me! Look at me! Famous feminists have sex in chauffeur-driven cars!!) come to life in a newish video that has Beyonce gyrating energetically and offering what anthropologists call presenting posture; bottoms up, as it were.

It's all very Discovery Channel, but it is art?

This new focus on the bottom has apparently prompted a huge increase in buttock enhancement surgery — like a 175% increase in the last decade. A Miami surgeon claims it's all due to the ample bottoms of such celebs as Kim Kardashian or Nicki Minaj. No surprise there. Cultural norms about bum size are changing, as anyone who can remember the initial furor over Jennifer Lopez' posterior can attest. Her backside now looks anemic compared to some.

But there's a dark cloud on the derriere horizon: Now that everyone wants a lot of junk in the trunk, illegal buttock enhancements are on the rise. A recent report at vice.com about an epidemic of black-market butt injections says disfigurement and death are possibilities if you put your assets into the wrong hands.

The article describes over-inflated rears pumped up with industrial-grade silicone or even concrete (seriously), and how those materials eventually cause cancerous tumours, skin lesions and disintegrating or exploding bums.

Talk about flying by the seat of your pants.

Who you gonna call? Probably famed Florida buttock wrangler Dr. Constantino Mendieta, who does a lot of backside enhancement plastic surgery. He says the buttock thing now is what breast enhancement was to the '60s generation.

“But butts are better. When you look at breasts, you have to look at a face. There is no room to fantasize," the doc tells vice.com

"But when you turn it around, there is no face anymore. You’re free to put whatever face you want on that booty.”

Wow! He must be fun at parties. So there you have it: the giant bottom is a far better aid to the complete objectification of women than the giant bosom. Glad to get that cleared up. Gluteal adipose tissue is where it's at, and who knew?

You'd never infer that from Beyonce's video or Miley's twerking or Kim's belfies.